EP3214218A1

EP3214218A1 - Laundry treating apparatus and control method thereof

Info

Publication number: EP3214218A1
Application number: EP15855184.6A
Authority: EP
Inventors: Hwanjin JUNG; Naeun Kim; Sanghyun Lee; Bonkwon Koo
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2014-10-27
Filing date: 2015-10-27
Publication date: 2017-09-06
Also published as: CN107109762A; KR20160049367A; US9863077B2; US20160115632A1; WO2016068575A1; CN107109762B; KR102196183B1; EP3214218A4

Abstract

Disclosed are a laundry treatment machine and a method for controlling the same. In operation of a pump for circulating and draining water, since the load of water to be drained is sensed and whether an error occurs due to foreign substances is determined based on a current and a rotation speed of a motor included in the pump, unnecessary operation of the pump may not be performed, damage of the pump due to overload may be prevented, noise due to pump operation in overloaded state may be solved, and the efficiency of pump control may be improved.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a laundry treatment machine and a method for controlling the same and, more particularly, to a laundry treatment machine for controlling a motor by sensing a load state based on operation of a pump for drainage and circulation of water, and a method for controlling the laundry treatment machine.

2. Description of the Related Art

In general, a laundry treatment machine performs a washing process using friction between laundry and a tub, which rotates by receiving a driving force from a motor, after detergent, water and the laundry are inserted into the tub, and thus can wash the laundry without damaging or tangling the laundry.
The general laundry treatment machine is configured to supply water into the tub, drain a part of water, supply water again, and then completely drain water as a washing process proceeds.
To circulate or drain water, the laundry treatment machine includes a pump attached to a drain hose connected to the tub, and the pump includes a motor. As the pump operates due to the motor, water flowing toward a drain is supplied into the tub again through a circulation hose or is drained through the drain hose.
When the flow of water is controlled as described above, the pump can brake if the pump continues operating after water is completely drained or stops operating while water is not completely drained.
In addition, if the drain is clogged with foreign substances, water is not normally drained. In this case, since water is not completely drained, the pump continues operating and thus is overloaded due to the abnormal flow of water.
Accordingly, a method for controlling the pump by sensing a load state of the tub or the drain hose is necessary.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a laundry treatment machine for sensing a voltage applied to a motor included in a pump for circulation and drainage of water to determine a load state of water inside a tub, and controlling operation of the motor depending on the determined load state, and a method for controlling the laundry treatment machine.
In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a laundry treatment machine including a motor included in a pump for draining or circulating water, to operate the pump, a motor driver for supplying operation power to the motor, a motor controller for setting a rotation speed of the motor and applying a signal for controlling the motor to the motor driver, a current sensor for measuring a current of the operation power supplied from the motor driver to the motor, a speed sensor for measuring a rotation speed of the motor, a water level sensor for measuring a level of water in a tub, and a main controller for applying a control command to the motor controller to start or stop operation of the motor, wherein the main controller controls the motor to stop by determining a load state of water and determining whether the level of water is zero, based on the current measured by the current sensor and the rotation speed of the motor measured by the speed sensor.
In accordance with another aspect of the present invention, there is provided a method for controlling a laundry treatment machine, the method including operating a motor of a pump to drain water if a water drain command is applied, measuring a current and a rotation speed of the motor, determining whether the current or the rotation speed varies by a specific reference value or more, stopping the motor if the current or the rotation speed varies by the reference value or more, and driving the motor again to complexly drain water after a specific period of time passes.

Effects of invention

A laundry treatment machine and a method for controlling the same according to embodiments of the present invention achieve the following effect. In operation of a pump for circulating and draining water, since the load of water to be drained is sensed and whether an error occurs due to foreign substances is determined based on a current and a rotation speed of a motor included in the pump, unnecessary operation of the pump may not be performed, damage of the pump due to overload may be prevented, noise due to pump operation in overloaded state may be solved, and the efficiency of pump control may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a laundry treatment machine according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing the configurations of a tub and a pump of the laundry treatment machine, according to an embodiment of the present invention;
FIG. 3 is a block diagram of the laundry treatment machine according to an embodiment of the present invention;
FIG. 4 is a schematic diagram showing signal information depending on sensing of the load of the laundry treatment machine, according to an embodiment of the present invention;
FIG. 5 is a graph showing the relationship between a voltage and a rotation speed of the motor in controlling the laundry treatment machine, according to an embodiment of the present invention; and
FIG. 6 is a flowchart of a method for controlling the laundry treatment machine, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail by explaining embodiments of the invention with reference to the attached drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to one of ordinary skill in the art. In the drawings, like reference numerals denote like elements.
The terms "module" and "unit" used to signify components are used herein to help the understanding of the components and thus should not be construed as having specific meanings or functions. Accordingly, the terms "module" and "unit" may be used interchangeably.
FIG. 1 is a perspective view of a laundry treatment machine 1 according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the configurations of a tub and a pump 11 of the laundry treatment machine 1, according to an embodiment of the present invention.
Referring to FIGS. 1 and 2, the laundry treatment machine 1 according to an embodiment of the present invention is a top-loading laundry treatment machine in which laundry is inserted into a tub from above. The top-loading laundry treatment machine includes the concept of a washing machine for performing washing, rinsing and spin-drying processes after laundry is inserted, or a drying machine for performing a drying process after wet laundry is inserted, and the following description is focused on the washing machine.
The washing machine 1 includes a casing for forming the exterior of the washing machine 1, manipulation keys for receiving a variety of control commands input by a user, a control panel for providing a user interface using, for example, a display for displaying information about an operation state of the washing machine 1, and a door for opening or closing an opening through which laundry enters or exits.
The control panel includes an input unit including a plurality of manipulation keys for manipulating an operation state of the laundry treatment machine 1, and a display unit for displaying the operation state of the laundry treatment machine 1.
The washing machine 1 includes the tub. The tub includes an outer tub 13 for accommodating water, and an inner tub 12 rotatably provided in the outer tub 13 to accommodate laundry.
The washing machine 1 may include a pulsator 14 rotatably provided at the bottom of the tub and, more particular, at the bottom of the inner tub 12.
A driving device (not shown) provides a driving force for rotating the inner tub 12 and/or the pulsator 14. In addition, a clutch (not shown) for selectively delivering the driving force of the driving device may be provided to rotate only the inner tub 12, to rotate only the pulsator 14, or to simultaneously rotate the inner tub 12 and the pulsator 14.
The inner tub 12 has a plurality of holes (not shown) and thus water supplied into the inner tub 12 flows through the holes to the outer tub 13. A water inlet valve (not shown) for opening or closing a water inlet hose (not shown) may be provided to supply water into the tub.
Water in the outer tub 13 is drained through a drain hose 15, and a drain valve (not shown) for opening or closing the drain hose 15, and the pump 11 for pumping water are provided.
In this case, the pump 11 discharges water through the drain hose 15 to the outside of the washing machine 1, or supplies water through a circulation hose 16 into the tub again, depending on a rotation direction thereof.
A spray nozzle 17 may be provided at an end of the circulation hose 16 and thus the circulated and re-supplied water may be sprayed.
When water is supplied into the tub through the water inlet hose, a water level sensor (not shown) senses the level of water. In this case, if water is supplied to a first point 18, the level of water corresponds to a height from the location of the drain hose 15 to the first point 18 and a level 19 is measured.
FIG. 3 is a block diagram of the laundry treatment machine 1 according to an embodiment of the present invention.
The washing machine 1 includes an input unit 170, an output unit 160, a water level sensor 156, a current sensor 152, a motor controller 120, a motor driver 130, a motor 140, a speed sensor 151, a driving controller 180, a driving device 190, and a main controller 110 for providing overall control to the washing machine 1. The washing machine 1 may further include a storage (not shown) for storing data.
In this case, the motor 140 is a motor of the pump 1 mounted on the drain hose 15 for drainage and circulation of water, and the motor controller 120 and the motor driver 130 are used to control operation of the motor 140 of the pump 11. Although the washing machine 1 further includes a plurality of sensors and additional devices related to the driving device 190, and other elements such as a water inlet valve and a drain valve, descriptions thereof are omitted herein and the following description is focused on a configuration for controlling the pump 11.
As an input means including the input unit 170 is manipulated, a specific signal is input to the main controller 110. The input unit 170 includes a plurality of manipulation keys provided on the control panel, and may further include a specific input means such as a touchpad.
The input unit 170 inputs setting data such as a washing mode, a washing temperature, a water level, or a reservation time, and inputs a control command for starting or stopping operation of the washing machine 1 depending on the setting data.
The output unit 160 outputs the setting data input through the input unit 170, e.g., the washing mode, the washing temperature, or the water level, and outputs process information such as a current washing process state and a remaining washing time.
The output unit 160 includes a display means for displaying the setting data or the process information in the form of text, a number, or an image. In addition, the output unit 160 may include a buzzer (not shown) or a speaker (not shown) for outputting a specific sound effect or an alarm, and a lamp (not shown) to be turned on or off to output an operation state or a warning.
The storage stores basic data for controlling operation of the washing machine 1, control data for controlling the operation, input and output data, and data input from a plurality of sensors while the washing machine 1 operates.
The driving controller 180 controls the driving device 190 to rotate based on a control command of the main controller 110. The driving device 190 includes another motor which rotates under control of the driving controller 180. The driving device 190 rotates at least one of the pulsator 14 or the inner tub 12.
The water level sensor 156 includes at least one sensor and measures the water level 19 in the tub. As described above, if water is supplied to the first point 18, the water level 19 is measured and provided to the main controller 110 and the motor controller 120.
The motor controller 120 generates a control signal for driving the motor 140 to operate the pump 11 depending on a control command of the main controller 110. The control signal generated in this case is a switching control signal, e.g., a pulse width modulation (PWM) signal.
In addition, the motor controller 120 generates a revolutions per minute (RPM) signal for controlling a rotation speed of the motor 140, as a control signal depending on a sensed load state of water. This signal sets a target rotation speed of the motor 140 and is variable depending on the load state of water.
In this case, the motor controller 120 outputs the PWM signal through a resistor-capacitor (RC) filter in such a manner that the PWM signal is input to the motor driver 130, and the RPM signal corresponds to a speed control voltage VSP, is set within a range from direct-current (DC) 1V to 4V, and is input to the motor driver 130.
The motor driver 130 supplies a current having a specific magnitude as motor driving power to the motor 140 based on the control signals input from the motor controller 120, i.e., the PWM signal and the RPM signal. In this case, the motor driver 130 includes a sensorless integrated circuit (IC) and a protection circuit.
As such, the motor 140 rotates and water of the drain hose 15 is drained or circulated and supplied into the tub again.
The motor 140 is a motor included in the pump 11 as described above. In this case, the motor 140 is a brushless DC (BLDC) motor.
The motor 140 rotates clockwise or counterclockwise under control of the motor controller 120 and the motor driver 130, and thus the pump 11 drains or circulates water.
For example, water is drained if the motor 140 rotates clockwise, and is circulated and supplied through the circulation hose 16 into the tub again if the motor 140 rotates counterclockwise.
The current sensor 152 measures the current supplied from the motor driver 130 to the motor 140 and inputs the same to the motor controller 120. In addition, the current sensor 152 inputs the sensed current to the main controller 110. The current sensor 152 includes an amplifier.
The speed sensor 151 measures a rotation speed of the motor 140 and inputs the same to the motor controller 120. In this case, the speed sensor 151 measures the speed by receiving a voltage of the motor 140, and a comparative value between a DC link voltage and a distribution value, and calculates RPM corresponding to the voltage.
In addition, the speed sensor 151 inputs the rotation speed of the motor 140 to the main controller 110.
The main controller 110 controls input and output of data to and from the input unit 170 and the output unit 160, and controls the data to be stored in the storage. The main controller 110 sets operation of the washing machine 1 based on the setting data input through the input unit 170, and thus controls the washing machine 1 to operate. As such, the washing machine 1 performs a washing process, a rinsing process, and a spin-drying process. A washer & dryer may further perform a drying process. The main controller 110 controls the display of the output unit 160 to display a washing mode, a washing time, a spin-drying time, a rinsing time, or a current operation state.
When the washing machine 1 operates and starts to wash laundry, the main controller 110 controls the drain valve not to drain water and controls the water inlet valve to supply water into the tub.
The main controller 110 controls the pump 11 to operate while the washing process or the rinsing process is performed, in such a manner that water is supplied through the circulation hose 16 into the tub again, and applies a control command to the motor controller 120 to drain water when the washing process and the rinsing process are completed.
In this case, the motor controller 120 generates a control signal for operation of the pump 11 depending on the control command of the main controller 110, and applies the same to the motor driver 130, and the motor driver 130 supplies motor driving power to the motor 140 to operate the pump 11.
The main controller 110 receives the current of the motor 140 of the pump 11 from the current sensor 152, receives the rotation speed of the motor 140 from the speed sensor 151, and determines whether the level of water in the tub is zero based on the current and the rotation speed. In this case, the current input from the current sensor 152 and to the main controller 110 is a value converted by an analog to digital converter (ADC), and the rotation speed input from the speed sensor 151 to the main controller 110 is a speed signal timer-processed by an encoder.
In addition, the main controller 110 determines whether overcurrent occurs and determines the load of water, based on the current and the rotation speed of the motor 140.
The main controller 110 inputs the results of determining whether the level of water is zero, whether overcurrent occurs, and the load, to the motor controller 120. As such, the motor controller 120 receives a zero water level signal, an overcurrent signal, and load data from the main controller 110, and reflects the same in a control signal for controlling the motor 140 of the pump 11.
In this case, when a set process is performed, if the pump 11 operates for drainage or circulation of water, the main controller 110 applies a control command to the motor controller 120 to control the pump 11 to start operation depending on the water level of the water level sensor 156. Furthermore, the main controller 110 applies a control command to the motor controller 120 to control the pump 11 to stop operation depending on whether the level of water is zero, while the pump 11 operates.
In addition, the main controller 110 determines whether the washing machine 1 normally operates, based on data input from a plurality of sensors, and outputs an error through the output unit 160 if an error occurs.
FIG. 4 is a schematic diagram showing signal information depending on sensing of the load of the laundry treatment machine 1, according to an embodiment of the present invention.
Referring to FIG. 4, the main controller 110 determines whether the level of water is zero, determines whether overcurrent occurs, and determines the load of water, based on the current of the motor 140, which is input from the current sensor 152, and the rotation speed (e.g., RPM) of the motor 140, which is input from the speed sensor 151.
The main controller 110 may determine that the level of water is zero, if the input rotation speed is increased and the current is reduced, according to a load sensing algorithm. In this case, the main controller 110 determines whether water is drained and the level of water is zero, in further consideration of the water level input from the water level sensor 156.
Based on the input rotation speed of the motor 140 of the pump 11 and the current, the main controller 110 determines the load of water and determines whether overcurrent occurs, if the rotation speed of the motor 140 of the pump 11 is reduced and the current is increased.
Depending on the determination result of the main controller 110, a zero water level signal, an overcurrent signal, and a load signal are input to the motor controller 120, and the current of the current sensor 152, the rotation speed of the speed sensor 151 (e.g., a currently measured RPM), and the water level of the water level sensor 156 are input to the motor controller 120. In addition, a target RPM of the motor 140 for driving the pump 11 is input from the main controller 110 to the motor controller 120.
The motor controller 120 generates a PWM signal based on the input data, sets a rotation speed of the motor 140, and inputs the rotation speed to the motor driver 130, and the motor driver 130 supplies driving power based thereon to the motor 140. The current sensor 152 senses and inputs an output current input from the motor driver 130 to the motor 140, to the motor controller 120 and the main controller 110, and measures and inputs a rotation speed of the speed sensor 151 to the motor controller 120 and the main controller 110 if the motor 140 operates.
As such, the motor controller 120 varies control of the motor 140 based on the target RPM, the actually measured RPM, and the current value in consideration of the load state of water, whether the level of water is zero, and whether overcurrent occurs.
In addition, the main controller 110 applies a control command to the motor controller 120 to stop or restart operation of the motor 140 based on the load state of water, whether the level of water is zero, whether overcurrent occurs, and variations in current value and rotation speed.
FIG. 5 is a graph showing the relationship between a voltage and a rotation speed of the motor 140 in controlling the laundry treatment machine 1, according to an embodiment of the present invention. In this case, a first line L1 shows an unloaded state, and a second line L2 shows a loaded state of water.
As illustrated in FIG. 5, a rotation speed RPM of the motor 140 is increased in proportion to a speed control voltage VSP of the motor controller 120.
In addition, when water is present in the tub, the relationship between the voltage and the rotation speed in the loaded state and the relationship in the unloaded state (i.e., zero water level) are compared as described below. At the same speed control voltage, the rotation speed of the motor 140 measured when water is not loaded (i.e., when the level of water is zero) is higher compared to that measured when water is present.
If cases of a first voltage V1 and a second voltage V2 are compared, the rotation speed of the motor 140 is increased in proportion to the voltage depending on the load of the water.
Accordingly, if a timing when water starts to be drained, a timing when the level of water is a half of an initial water level, and a timing when water is completely drained and thus the level of water is zero water are compared, the rotation speed of the motor 140 of the pump 11 is increased as the load of water is reduced.
In this case, if a drain filter is clogged with foreign substances, water may not be normally drained and thus a current for driving the motor 140 may be increased. In addition, it may be determined whether water is normally drained, based on a variation in the rotation speed of the motor 140 measured for a preset drain time.
As such, the main controller 110 may determine that an error occurs and thus output the error through the output unit 160.
FIG. 6 is a flowchart of a method for controlling the laundry treatment machine 1, according to an embodiment of the present invention.
If the washing machine 1 starts operation depending on setting data and drains water in a washing process or a rinsing process, the main controller 110 applies a drain command to the motor controller 120 (S310).
The motor controller 120 generates a control signal for controlling the motor 140 of the pump 11, and sets a voltage for setting a speed of the motor 140 (S320 and S330).
The motor driver 130 receives the control signal of the motor controller 120 and supplies driving power to the motor 140, and thus the motor 140 rotates and operates (S340).
In this case, the speed sensor 151 measures the rotation speed of the motor 140 (S360), and applies the measured rotation speed to the main controller 110 and the motor controller 120. The motor controller 120 generates a control signal for subsequent control of the motor 140 based on the input rotation speed.
The main controller 110 determines whether the measured rotation speed of the motor 140 is increased by a certain rate or more (S370). In this case, the main controller 110 determines whether the rotation speed of the motor 140 is increased by 33% or more compared to a pre-measured rotation speed.
If the rotation speed of the motor 140 is increased by the certain rate or more, the main controller 110 applies a motor stop command to the motor controller 120 (S400).
Meanwhile, the current sensor 152 measures a current applied from the motor driver 130 to the motor 140 (S380).
The main controller 110 compares the measured current value to a previous current value, and determines whether the current is reduced (S390). For example, the main controller 110 may determine whether the current is reduced by 90% or more.
If the current is reduced by a certain value or more, the main controller 110 applies a motor stop command to the motor controller 120 (S400).
Otherwise, if the current is not reduced or is reduced by a value less than the certain value, or if the speed is not increased or is increased by a rate less than the certain rate, the motor 140 continues operating. While the motor 140 operates, the rotation speed and the current value thereof are sensed and variations therein are monitored.
As such, the main controller 110 determines whether overcurrent is supplied to the motor 140, a load state, or whether the level of water is zero, based on the variations in the rotation speed and the current.
The main controller 110 stops the motor 140, counts the number of times that the motor 140 stops, and determines whether the number of times that the motor 140 stops is equal to or greater than a reference number (S410).
If the number of times that the motor 140 stops is less than the reference number, after a specific period of time passes (S420), the main controller 110 applies a motor driving command to the motor controller 120 to drive the motor 140 again.
Otherwise, if the number of times that the motor 140 stops is equal to or greater than the reference number, the main controller 110 controls the water level sensor 156 to measure the level of water (S430).
The main controller 110 determines whether water is completely drained to a designated level, based on the measured level of water (S450). If water is not completely drained, the motor 140 is driven again to operate the pump 11 again.
If water is completely drained, the main controller 110 determines that drainage is completed (S460), and the method proceeds to a subsequent process.
Therefore, according to the present invention, a load state of water and an error in drainage due to, for example, foreign substances are sensed and overcurrent supplied to a motor is determined depending on variations in rotation speed and current value of the motor. Thus, operation of the motor is controlled. As such, the motor may be protected, may achieve noise reduction, and thus may be controlled more efficiently.
Although all elements constituting the embodiments of the present invention are described to be integrated into a single one or to be operated as a single one, the present invention is not necessarily limited to such embodiments. According to embodiments, all of the elements may be selectively integrated into one or more and be operated as one or more within the object and the scope of the present invention
The preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

A laundry treatment machine comprising:
a motor comprised in a pump for draining or circulating water, to operate the pump;

a motor driver for supplying operation power to the motor;

a motor controller for setting a rotation speed of the motor and applying a signal for controlling the motor to the motor driver;

a current sensor for measuring a current of the operation power supplied from the motor driver to the motor;

a speed sensor for measuring a rotation speed of the motor;

a water level sensor for measuring a level of water in a tub; and

a main controller for applying a control command to the motor controller to start or stop operation of the motor,

wherein the main controller controls the motor to stop by determining a load state of water and determining whether the level of water is zero, based on the current measured by the current sensor and the rotation speed of the motor measured by the speed sensor.
The laundry treatment machine according to claim 1, wherein the motor controller stops the motor if a zero water level sensing signal or an overcurrent sensing signal is input from the main controller.
The laundry treatment machine according to claim 1, wherein the main controller determines whether overcurrent occurs or determines the load state, if the rotation speed of the motor is reduced and the current is increased.
The laundry treatment machine according to claim 1, wherein the main controller determines whether the level of water is zero, if the rotation speed is increased and the current is reduced.
The laundry treatment machine according to claim 1, wherein the main controller controls the motor to stop, if the rotation speed is increased by a certain rate or more.
The laundry treatment machine according to claim 5, wherein the main controller controls the motor to stop, if the rotation speed is increased by 33% or more.
The laundry treatment machine according to claim 1, wherein the main controller controls the motor to stop, if the current is reduced by a certain value or more.
The laundry treatment machine according to claim 7, wherein the main controller controls the motor to stop, if the current is reduced by 90% or more.
The laundry treatment machine according to claim 1, wherein the main controller counts a number of times that the motor stops, and determines whether water is completely drained, based on the level of water measured by the water level sensor, if the number of times that the motor stops is equal to or greater than a reference number.
The laundry treatment machine according to claim 1, wherein the main controller counts a number of times that the motor stops, and controls the motor to stop and then to be driven again after a specific period of time, if the number of times that the motor stops is less than a reference number.
A method for controlling a laundry treatment machine, the method comprising:
operating a motor of a pump to drain water if a water drain command is applied;

measuring a current and a rotation speed of the motor;

determining whether the current or the rotation speed varies by a specific reference value or more;

stopping the motor if the current or the rotation speed varies by the reference value or more; and

driving the motor again to complexly drain water after a specific period of time passes.
The method according to claim 11, wherein the determining comprises determining whether the current is reduced by 90% or more compared to a pre-measured current.
The method according to claim 11, wherein the determining comprises determining whether the rotation speed is increased by 33% or more compared to a pre-measured rotation speed.
The method according to claim 11, further comprising counting a number of times that the motor stops, when the motor stops,
wherein the motor is driven again after a specific period of time passes, if the number of times that the motor stops is less than a reference number.
The method according to claim 14, further comprising:
sensing a level of water if the number of times that the motor stops is equal to or greater than the reference number; and

driving the motor again if water is not complexly drained.